Skill for designing and implementing backend APIs. Includes Zero Script QA methodology for validating APIs without test scripts. Triggers: API design, REST API, backend, endpoint, API 설계, API設計, API设计
Implements backend APIs using RESTful principles and validates them with Zero Script QA methodology.
/plugin marketplace add popup-studio-ai/bkit-claude-code/plugin install bkit@bkit-marketplaceThis skill is limited to using the following tools:
Backend API implementation and script-free QA
Implement backend APIs that can store and retrieve data. Validate with structured logs instead of test scripts.
docs/02-design/
└── api-spec.md # API specification
src/api/ # API implementation
├── routes/
├── controllers/
└── services/
docs/03-analysis/
└── api-qa.md # QA results
| Level | Application Method |
|---|---|
| Starter | Skip this Phase (no API) |
| Dynamic | Use bkend.ai BaaS |
| Enterprise | Implement APIs directly |
Instead of writing test scripts, validate with structured debug logs
[API] POST /api/users
[INPUT] { "email": "test@test.com", "name": "Test" }
[PROCESS] Email duplicate check → Passed
[PROCESS] Password hash → Complete
[PROCESS] DB save → Success
[OUTPUT] { "id": 1, "email": "test@test.com" }
[RESULT] ✅ Success
Advantages:
- Save test code writing time
- See actual behavior with your eyes
- Easy debugging
REpresentational State Transfer - an architecture style for designing web services.
| Principle | Description | Example |
|---|---|---|
| 1. Client-Server | Separation of concerns between client and server | UI ↔ Data storage separated |
| 2. Stateless | Each request is independent, server doesn't store client state | Auth token included with each request |
| 3. Cacheable | Responses must indicate if cacheable | Cache-Control header |
| 4. Uniform Interface | Interact through consistent interface | Detailed below |
| 5. Layered System | Allow layered system architecture | Load balancer, proxy |
| 6. Code on Demand | (Optional) Server can send code to client | JavaScript delivery |
The core of RESTful APIs is a uniform interface.
✅ Good (nouns, plural)
GET /users # User list
GET /users/123 # Specific user
POST /users # Create user
PUT /users/123 # Update user
DELETE /users/123 # Delete user
❌ Bad (using verbs)
GET /getUsers
POST /createUser
POST /deleteUser/123
| Method | Purpose | Idempotent | Safe |
|---|---|---|---|
GET | Read | ✅ | ✅ |
POST | Create | ❌ | ❌ |
PUT | Full update | ✅ | ❌ |
PATCH | Partial update | ❌ | ❌ |
DELETE | Delete | ✅ | ❌ |
Idempotent: Same result even if requested multiple times Safe: Doesn't change server state
2xx Success
├── 200 OK # Success (read, update)
├── 201 Created # Creation success
└── 204 No Content # Success but no response body (delete)
4xx Client Error
├── 400 Bad Request # Invalid request (validation failure)
├── 401 Unauthorized # Authentication required
├── 403 Forbidden # No permission
├── 404 Not Found # Resource not found
└── 409 Conflict # Conflict (duplicate, etc.)
5xx Server Error
├── 500 Internal Error # Internal server error
└── 503 Service Unavailable # Service unavailable
// Success response
{
"data": {
"id": 123,
"email": "user@example.com",
"name": "John Doe"
},
"meta": {
"timestamp": "2026-01-08T10:00:00Z"
}
}
// Error response
{
"error": {
"code": "VALIDATION_ERROR",
"message": "Email format is invalid.",
"details": [
{ "field": "email", "message": "Please enter a valid email" }
]
}
}
// List response (pagination)
{
"data": [...],
"pagination": {
"page": 1,
"limit": 20,
"total": 100,
"totalPages": 5
}
}
1. Use lowercase
✅ /users/123/orders
❌ /Users/123/Orders
2. Use hyphens (-), avoid underscores (_)
✅ /user-profiles
❌ /user_profiles
3. Express hierarchical relationships
✅ /users/123/orders/456
4. Filtering via query parameters
✅ /users?status=active&sort=created_at
❌ /users/active/sort/created_at
5. Version management
✅ /api/v1/users
✅ Header: Accept: application/vnd.api+json;version=1
| Tool | Features |
|---|---|
| OpenAPI (Swagger) | Industry standard, auto documentation |
| Postman | Testing + documentation |
| Insomnia | Lightweight API client |
templates/pipeline/phase-4-api.template.mdtemplates/pipeline/zero-script-qa.template.mdPhase 5: Design System → APIs are ready, now build UI components
This skill should be used when the user asks to "create a slash command", "add a command", "write a custom command", "define command arguments", "use command frontmatter", "organize commands", "create command with file references", "interactive command", "use AskUserQuestion in command", or needs guidance on slash command structure, YAML frontmatter fields, dynamic arguments, bash execution in commands, user interaction patterns, or command development best practices for Claude Code.
This skill should be used when the user asks to "create an agent", "add an agent", "write a subagent", "agent frontmatter", "when to use description", "agent examples", "agent tools", "agent colors", "autonomous agent", or needs guidance on agent structure, system prompts, triggering conditions, or agent development best practices for Claude Code plugins.
This skill should be used when the user asks to "create a hook", "add a PreToolUse/PostToolUse/Stop hook", "validate tool use", "implement prompt-based hooks", "use ${CLAUDE_PLUGIN_ROOT}", "set up event-driven automation", "block dangerous commands", or mentions hook events (PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification). Provides comprehensive guidance for creating and implementing Claude Code plugin hooks with focus on advanced prompt-based hooks API.